1. Field of the Invention
The present invention relates generally to a seed drill of the type used to plant seeds in agricultural operations. The term "seed drill" is intended herein to encompass various types of seed planters including traditional seed drills, row planters and other similar devices. More particularly, the invention relates to such a seed drill which incorporates a disc blade soil opener for creating seed trenches with a scraper/soil firming attachment. The scraper/soil firming attachment simultaneously controls the movement of soil, firms the soil on each side of the disc blade(s) and scrapes the outside of the disc blade(s).
2. Description of the Related Art
Modern farmers are faced with a variety of problems, including increased concern for soil erosion, crop residue management and rising production costs with stagnant crop prices. One way farmers are successfully addressing each of these concerns is with "low till" or "no till" farming operations. In a no till operation, succeeding crops are planted directly into the soil without disturbing the crop residue from prior crops. This practice reduces costs since soil preparation, such as plowing, discing and harrowing, etc., is eliminated. Furthermore, by leaving the prior crop residue in the field, soil erosion is minimized.
Several factors determine the effectiveness of no till operations, particularly including the problem of depositing new seeds such that they are at the proper soil depth and are surrounded by soil. Various seed drills have been devised to accomplish this task. One common type of no till seed drill uses a double disc soil opener in which a pair of disc blades are positioned on respective sides of a common axle. The disc blades converge toward each other in front of the axle, virtually meeting each other at a point where they contact the soil, and diverge away from each other behind the axle. The blade axes can be aligned or slightly staggered, with the converging forward portions of the blades opening a seed trench and with the diverging trailing blade portions spreading the trench. A seeder is disposed above the disc blades, dropping seeds and, optionally, fertilizer, within the space between the blades. Typically a trailing press wheel compacts the trench around the seeds to provide for good seed to soil contact. In another common seed drill type, a single disc blade is mounted on a shaft at a greater angle across the path of movement of the seed drill. Finally, some seed drills use fixed shank openers or "hoe drills" to open soil for seed deposition.
In no till farming, soil conditions are, almost by definition, less than ideal. The soil surface is generally somewhat irregular, and crop residue from prior crops acts as debris which can collect around deposited seeds, preventing good soil to seed contact. Regardless of the type of soil opener used on a seed drill, the debris often collects on the soil opener blades, clogging them or impeding their proper operation. Finally, as the soil opener forces soil outward to create the seed trench, soil "blow-out" can occur, i.e. the uncontrolled dirt flow from the outside of the disc blade(s) such that the soil cannot be redeposited in the trench by the trailing press wheel. The inventor has found that soil blow-out is a factor of soil conditions but also of the speed of movement of the seed drill, i.e. the faster the seed drill is pulled, the worse the soil blow-out.
Prior art attempts to control soil blow-out have included the addition of various types of leading coulters placed directly in front of each soil opener. In effect, this is an attempt to loosen the soil, thus limiting or eliminating the soil conditions which result in blow-out. These attempts, although they have somewhat lessened the condition, do not eliminate blow-out and the addition of coulter blades, axles, bearings, etc. add significantly to the complexity, cost, and maintenance of the seed drill.
Other inventors have added scrapers to soil openers to scrape debris off of the disc blade or blades as they rotate. Typically these scrapers are suspended from the seed drill frame such that they are positioned adjacent to and are stationary with respect to the rotating blade or blades, thus constantly scraping debris form the blades. However, these scrapers merely clear the debris off of the blades after it collects and do nothing to prevent the collection of debris on the blades, or, particularly around the disc blade axles and bearings. Furthermore, they do nothing to address the problem of soil blow-out.
Accordingly, it is clear that a need exists for an improved seed drill attachment for jointly addressing the problems of soil blow-out and soil opener blade scraping, particularly in no till or low till farming operations. Such an attachment should allow the seed drill to be reliably operated at higher speeds without unduly increasing the incidence of soil blow-out. Finally, the attachment should be economical to manufacture and install and should not add significantly to the cost and complexity or maintenance of the seed drill.